title: Effect of superior oblique weakening on vertical alignment and horizontal and vertical incomitance in patients with A-pattern strabismus.
abstract: OBJECTIVE
  To determine the relationship between the magnitude of preoperative A pattern and the correction of vertical alignment and horizontal and vertical incomitance in patients treated with superior oblique muscle-weakening procedures for A-pattern strabismus.
  
  
  METHODS
  The records of consecutive patients who underwent surgery for A-pattern strabismus between 1997 and 2008 were retrospectively reviewed. Both horizontal (from up- to downgaze) and vertical (from right to left gaze) incomitance were assessed.
  
  
  RESULTS
  Twenty-six patients were treated with superior oblique muscle-weakening procedures (either tendon spacer or nasal or posterior 7/8 temporal tenotomy, with or without simultaneous rectus muscle surgery). In these patients, the A pattern improved from 36Δ preoperatively (range, 15Δ-75Δ) to 6Δ postoperatively (range, 0Δ-16Δ). The magnitude of the reduction in A pattern correlated strongly with the size of preoperative A pattern (r=0.92), whereas the reduction in the magnitude of the vertical incomitance correlated weakly with the magnitude of the preoperative deviation (r=0.56). There was no significant correlation between the magnitude of the A pattern and the vertical incomitance (r=0.25). Of the 9 patients with preexisting primary position vertical deviation≥6Δ, 5 required additional vertical rectus muscle surgery.
  
  
  CONCLUSIONS
  Superior oblique muscle-weakening surgery improved the A pattern but did not reliably improve the primary position vertical deviation and lateral gaze vertical incomitance. Patients with associated primary position vertical deviations of >6Δ preoperatively tended to have a greater likelihood of requiring additional strabismus surgery.
authors.affiliation: Department of Ophthalmology, Royal Hallamshire Hospital, Sheffield, United Kingdom. ctu195@yahoo.co.uk
authors.forename: Tsiang
authors.initials: T
authors.lastname: Ung
authors.forename: Naz
authors.initials: N
authors.lastname: Raoof
authors.forename: John
authors.initials: J
authors.lastname: Burke
mesh_terms: D004948:Esotropia / Q000503:physiopathology / Q000601:surgery*; D005099:Exotropia / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D009801:Oculomotor Muscles / Q000503:physiopathology / Q000601:surgery*; D013508:Ophthalmologic Surgical Procedures; D012189:Retrospective Studies; D013710:Tendons / Q000601:surgery; D058971:Tenotomy; D016896:Treatment Outcome; D015348:Vision, Binocular / Q000502:physiology